1. Field of the Invention
The invention relates to the structure of a filter and, more particularly, to the structure of an in-tank type fuel filter installed in a vehicular fuel tank.
2. Description of Related Art
Hereinafter, an in-tank type fuel filter installed in a vehicular fuel tank according to the related art will be described as an example. Note that the invention should not be limited to in-tank type fuel filters.
FIG. 16 shows a fuel tank 1 installed in a vehicle. A fuel pump 3 for delivering fuel to a fuel injection system 4 is disposed in the fuel tank 1. A fuel filter 2 is attached to the fuel pump 3 at its upstream inlet via a coupling member 7. FIG. 17 shows details of the fuel filter 2. The fuel filter 2 is coupled with the fuel pump 3 via the coupling member 7, and abuts at the other end thereof on a bottom wall 9 of the fuel tank 1. Thus, even if the fuel level has decreased, a sufficient amount of fuel can be pumped up.
The fuel filter 2 is composed of a filter member 5 constructed of a mesh screen made from a synthetic resin and having a multitude of apertures formed therein, and of a protector 6 disposed inside the filter member 5. The protector 6 is made from a synthetic resin, offers a communication passage leading to the fuel pump 3, and prevents cohesion of the filter member 5.
Because the in-tank type fuel filter 2 as described above has the protector 6 inside, it is advantageous in that cohesion of the filter member 5 can be prevented, that a sufficient inner space 8 can be ensured, and that the fuel filter 2 can be installed with the filter member 5 pressed onto the bottom wall 9 of the fuel tank 1.
However, the fuel filter 2 has the following problems.
First of all, the overall weight and costs increase because of the protector 6.
Because of the structure wherein rigidity of the protector 6 is utilized to press the fuel filter 2 onto the bottom wall 9 of the fuel tank 1, the filter member 5 is apt to be abraded and thus is disadvantageous in terms of durability. Further, vibrations of the pump are conveyed via the protector 6 and cause discomfort to human bodies as harmful noise.
Furthermore, since a molded article made from a synthetic resin is used as the protector 6, the protector 6 tends toward deformation such as warp when soaked in fuel. The filter member 5 is also deformed simultaneously with the deformation of the protector 6, and decreases in durability as a result.
Furthermore, a corner portion of the protector 6 abrades the filter member 5 at a portion that is in contact with the bottom wall 9 of the fuel tank 1. This threatens to accelerate abrasion of the filter member 5 and make it useless.
Further, since the mesh screen of the related art is planar, the filtration area is limited even if it is used. The filter is inevitably enlarged if an attempt has been made to increase the filtration area and prolong the period of endurance.
It is thus an object of the invention to provide a filter that eliminates the inconveniences of a liquid filter such as the in-tank type fuel filter, that can be manufactured at low costs, that offers high durability, and that is compact in size.
To achieve the above object, according to a first aspect of the invention, there is provided a filter comprising a filter member forming at least two opposed faces, an inner space surrounded by the filter member for accumulation of a liquid, and a coupling member establishing communication between the inner space and the outside to deliver the liquid in the inner space to the outside, wherein the liquid is removed of foreign matters by passing through the filter member and is discharged via the coupling member. A plurality of convexo-concaves are provided on at least one face of the filter member. Due to this construction, even though the protector has been dispensed with, a sufficient inner space can be guaranteed and the filtration area can be increased.